All antiepilepic medications have been shown to be associated with higher risks of fetal abnormalities (mostly for spina bifida) since at least 1983 with the risks being related to the strength of medication used and use of more than one drug.[1][2] Valproate has also been recognised as sometimes causing a specific facial changes ("facial phenotype") termed "fetal valproate syndrome".[3] Sodium valproate has been associated with the rare condition Paroxysmal tonic upgaze of childhood from childhood exposure(Epileptic Disord. 2007 Sep;9(3):332-6) and also fetal exposure (This condition resolved after discontinuing valproate therapy. Ouvrier-Billson syndrome (J Child Neurol. 1988 Jul;3(3):177-80) is the name used for this condition, to honor the discoverer.

A 2005 study found rates of autism among children exposed to sodium valproate before birth in the cohort studied were 8.9%.[5] The normal incidence for autism in the general population is estimated at less than one percent.[6] It has been suggested that Valproate may best be avoided in women with localisation epilepsy, where there are more effective and less risky alternatives such as carbamazepine.[4]

A 2008 study [8] also suggested a correlation between higher rates of autism in children whose mothers were treated for seizure disorders during pregnancy using sodium valproate (less than 1% for children who didn't receive the drug in vitro vs. 6.3% for children who did). However, only 632 children were followed in this study, prompting criticism that this study was too small to rely on to say whether there was a definitive correlation between the use of sodium valproate in pregnant mothers and higher autism rates in their children, or whether other anti-seizure medications used during pregnancy don't cause this effect.